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OT: Help choosing an antenna for ATSC

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potuncle at gmail

Jun 20, 2005, 5:20 PM

Post #1 of 7 (948 views)
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OT: Help choosing an antenna for ATSC

I'm trying to receive the 5 local ATSC stations and not having good
luck with my current antenna. My current antenna is a medium sized
VHF/UHF/FM directional antenna with a mast mounted pre-amp. I cannot
get a decent signal on all the stations without rotating the antenna.
My inital plans were to have MythTV control my rotor whenever it
changed the channel, but it seems that MythTV cannot run channel
change scripts when using a DVB tuner card.

So, if possible, I'd like to replace my antenna with an
omnidirectional UHF-only one. Of the 5 stations I am trying to
receive, 3 have transmitters that are located 1.7 miles from me at 208
degrees, and 2 have transmitters 8 miles from me at 17 degrees. There
are some surrounding tall trees twoards the South of my home.

Anyone have an antenna that they can suggest?

Thanks much,

Jason
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mwahal at gmail

Jun 20, 2005, 5:26 PM

Post #2 of 7 (900 views)
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Re: OT: Help choosing an antenna for ATSC [In reply to]

Channel Master 4228. The best of all. Search for it on the internet.

On 6/20/05, Jason Weinstein <potuncle [at] gmail> wrote:
> I'm trying to receive the 5 local ATSC stations and not having good
> luck with my current antenna. My current antenna is a medium sized
> VHF/UHF/FM directional antenna with a mast mounted pre-amp. I cannot
> get a decent signal on all the stations without rotating the antenna.
> My inital plans were to have MythTV control my rotor whenever it
> changed the channel, but it seems that MythTV cannot run channel
> change scripts when using a DVB tuner card.
>
> So, if possible, I'd like to replace my antenna with an
> omnidirectional UHF-only one. Of the 5 stations I am trying to
> receive, 3 have transmitters that are located 1.7 miles from me at 208
> degrees, and 2 have transmitters 8 miles from me at 17 degrees. There
> are some surrounding tall trees twoards the South of my home.
>
> Anyone have an antenna that they can suggest?
>
> Thanks much,
>
> Jason
> _______________________________________________
> mythtv-users mailing list
> mythtv-users [at] mythtv
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
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doug at ties

Jun 20, 2005, 5:38 PM

Post #3 of 7 (899 views)
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Re: OT: Help choosing an antenna for ATSC [In reply to]

Jason Weinstein wrote:
> So, if possible, I'd like to replace my antenna with an
> omnidirectional UHF-only one. Of the 5 stations I am trying to
> receive, 3 have transmitters that are located 1.7 miles from me at 208
> degrees, and 2 have transmitters 8 miles from me at 17 degrees. There
> are some surrounding tall trees twoards the South of my home.

These clusters are fairly close to 180 degrees from one another, and
fairly close to you, so you might try a bowtie-type antenna, perhaps
even pulling the reflector off one like this one:
http://antennasdirect.com/DB2_Indoor_antenna.html

-Doug

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bill-mythtv at carpenter

Jun 20, 2005, 5:42 PM

Post #4 of 7 (898 views)
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Re: OT: Help choosing an antenna for ATSC [In reply to]

jw> So, if possible, I'd like to replace my antenna with an
jw> omnidirectional UHF-only one. Of the 5 stations I am trying to

mw> Channel Master 4228. The best of all. Search for it on the

Maybe so, but the 4228 is not omnidirectional. In fact, it's highly
directional with a 10-15 degree face.

But that leads me to a question I've been wondering. Suppose I have a
couple of antennae on my rooftop. Can I just combine them onto a
single coax with a splitter/combiner? If that works, is there any
practical limit on the number of antennae I can combine that way?

(I already combine my small-dish satellite signal with my off-air
antenna via a diplexor, but I'm thinking of an additional,
differently-oriented off-air antenna if I can do it without another
cable run.)
--
bill-mythtv [at] carpenter (WJCarpenter) PGP 0x91865119
38 95 1B 69 C9 C6 3D 25 73 46 32 04 69 D6 ED F3

david.asher at caviumnetworks

Jun 20, 2005, 6:48 PM

Post #5 of 7 (899 views)
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Re: OT: Help choosing an antenna for ATSC [In reply to]

My understanding is that you can, but you need pass filters to prevent
causing multi-path reception problems.

Basically, get a pass filter for the 2 channels in one direction and
then you should be able to combine that with the 5 channels from the
other direction... If you're unlucky you might need a corresponding
notch filter on the 5 channel side -- or equivalently its own pass
filter for its 5 channels. This, of course, get much more complicated
if the channels are near each other in frequency.

Disclaimer: I've never tried this myself, but I looked into it on
avsforum when setting up my attic antenna... In the end I decided to
only go with one set of stations to ease the complexity (and attic
space). I recommend searching around in avsforum's HDTV reception
forums for WAYYYY more knowledgable people than myself.

David.

WJCarpenter wrote:

>jw> So, if possible, I'd like to replace my antenna with an
>jw> omnidirectional UHF-only one. Of the 5 stations I am trying to
>
>mw> Channel Master 4228. The best of all. Search for it on the
>
>Maybe so, but the 4228 is not omnidirectional. In fact, it's highly
>directional with a 10-15 degree face.
>
>But that leads me to a question I've been wondering. Suppose I have a
>couple of antennae on my rooftop. Can I just combine them onto a
>single coax with a splitter/combiner? If that works, is there any
>practical limit on the number of antennae I can combine that way?
>
>(I already combine my small-dish satellite signal with my off-air
>antenna via a diplexor, but I'm thinking of an additional,
>differently-oriented off-air antenna if I can do it without another
>cable run.)
>
>
>------------------------------------------------------------------------
>
>_______________________________________________
>mythtv-users mailing list
>mythtv-users [at] mythtv
>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
>

michael at anthon

Jun 20, 2005, 7:40 PM

Post #6 of 7 (898 views)
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Re: OT: Help choosing an antenna for ATSC [In reply to]

David Asher wrote:

> My understanding is that you can, but you need pass filters to prevent
> causing multi-path reception problems.

<snipped stuff about filters>

If the signal strengths from the 2 separate antennas for each of the
signals in question are significantly different in level then you can
probably get away without the filters, particularly with digital. The
problem you may find is that most directional antennas have a fairly
significant rear lobe and given that the 2 sources are close to 180
degrees apart you may find the multi-path reception is a problem. The
other way around this is to arrange the antennas and cable lengths such
that the signals from the 2 actually combine correctly BUT that is
basically impossible to arrange for a broad frequency range. Either way
you need some pretty good test gear to set this sort of thing up.

The other option that comes to mind is to throw another tuner card into
the computer and use 2 antennas with separate feeds to the separate
tuners then you can configure mythtv to match up the channels and
tuners. Given the prices of tuner cards and cabling bits required to do
fancy combinations of antennas it might actually work out cheaper anyway
with the added benefit of being able to record 2 things at once (as long
as they are on separate antennas)

Cheers,
Michael
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mlynch at gcom

Jun 21, 2005, 6:12 AM

Post #7 of 7 (894 views)
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Re: OT: Help choosing an antenna for ATSC [In reply to]

Jason Weinstein wrote:
> I'm trying to receive the 5 local ATSC stations and not having good
> luck with my current antenna. My current antenna is a medium sized
> VHF/UHF/FM directional antenna with a mast mounted pre-amp. I cannot
> get a decent signal on all the stations without rotating the antenna.
> My inital plans were to have MythTV control my rotor whenever it
> changed the channel, but it seems that MythTV cannot run channel
> change scripts when using a DVB tuner card.
>
> So, if possible, I'd like to replace my antenna with an
> omnidirectional UHF-only one. Of the 5 stations I am trying to
> receive, 3 have transmitters that are located 1.7 miles from me at 208
> degrees, and 2 have transmitters 8 miles from me at 17 degrees. There
> are some surrounding tall trees twoards the South of my home.
>
> Anyone have an antenna that they can suggest?
>

I use an amplified multi-directional from Rectron (sp?) and I can
consistantly pick up stations from ~35 miles away. Sometimes I
pick up stations ~60 miles away and occasionally I pick up stations
120 miles away. And, yes, I'm talking about ATSC transmission.

The terrain where I live is flat prairie land with a few trees.
I have a large grain elevtor between 3 transmitting positions and
my antenna and this doesnt' cause any problems. My antenna is
mounted about 15' above ground and is actually BELOW the peak of
my roof.

--
Michael J. Lynch

What if the hokey pokey IS what it's all about -- author unknown

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